A union is things coming together, or uniting, to make one. When the thirteen colonies that became the United States came together, they formed a union. Marriage is another kind of union.

Workers come together to form trade unions so that together they can have a stronger voice negotiating with their employer. The word famously occurs in the Preamble (the introduction) to the United States Constitution: "We the people of the United States, in Order to form a more perfect Union...do ordain and establish this Constitution...." You may recognize the Latin root unum in union, as in e pluribus unum "from many, one," the motto on the seal of the United States.

Primary Meanings of union

the state of being joined or united or linked
a political unit formed from previously independent people or organizations
of trade unions
the state of being a married couple voluntarily joined for life (or until divorce)
healing process involving the growing together of the edges of a wound or the growing together of broken bones
a device on a national flag emblematic of the union of two or more sovereignties (typically in the upper inner corner)
Full Definitions of union

n the state of being joined or united or linked

“there is strength in union
the state of lacking unity
show 14 types...
hide 14 types...
coalition, fusion
the state of being combined into one body
connectedness, connection, link
the state of being connected
colligation, conjugation, conjunction, junction
the state of being joined together
the state of being connected together as in memory or imagination
a close and intimate union
the union (or attempted fusion) of different systems of thought or belief (especially in religion or philosophy)
anastomosis, inosculation
a natural or surgical joining of parts or branches of tubular structures so as to make or become continuous
the junction between two neurons (axon-to-dendrite) or between a neuron and a muscle
alliance, confederation
the state of being allied or confederated
federalisation, federalization
the state of being under federal control
the state or condition of touching or of being in immediate proximity
the state of being linked together as in a chain; union in a linked series
interconnectedness, interconnection
a state of being connected reciprocally
coherence, coherency, cohesion, cohesiveness
the state of cohering or sticking together
Type of:
the way something is with respect to its main attributes

n the act of making or becoming a single unit

“the union of opposing factions”
conjugation, jointure, unification, uniting
the termination or destruction of union
show 5 types...
hide 5 types...
coalescence, coalescency, coalition, concretion, conglutination
the union of diverse things into one body or form or group; the growing together of parts
reunification, reunion
the act of coming together again
tribalisation, tribalization
the act of making tribal; unification on a tribal basis
having the function of uniting a group of similar things
an annual school or university reunion for graduates
Type of:
combination, combining, compounding
the act of combining things to form a new whole

n the occurrence of a uniting of separate parts

“lightning produced an unusual union of the metals”
show 8 types...
hide 8 types...
union of sperm and egg in sexual reproduction
fusion, merger, unification
an occurrence that involves the production of a union
combine, combining
an occurrence that results in things being united
(genetics) a combining of genes or characters different from what they were in the parents
(physics) a combining of charges or transfer of electrons in a gas that results in the neutralization of ions; important for ions arising from the passage of high-energy particles
combining into a solid mass
mix, mixture
an event that combines things in a mixture
conglobation, conglomeration
an occurrence combining miscellaneous things into a (more or less) rounded mass
Type of:
happening, natural event, occurrence, occurrent
an event that happens

n a set containing all and only the members of two or more given sets

“let C be the union of the sets A and B”
join, sum
direct sum
a union of two disjoint sets in which every element is the sum of an element from each of the disjoint sets
Type of:
a group of things of the same kind that belong together and are so used

n a political unit formed from previously independent people or organizations

show 9 types...
hide 9 types...
confederacy, confederation, federation
a union of political organizations
the union of Greece and Cyprus (which is the goal of a group of Greek Cypriots)
an association of states or organizations or individuals for common action
customs union
an association of nations to promote free trade within the union and set common tariffs for nations that are not members
a federation of tribes (especially Native American tribes)
Creek Confederacy
a North American Indian confederacy organized by the Muskogee that dominated the southeastern part of the United States before being removed to Oklahoma
Hanseatic League
a commercial and defensive confederation of free cities in northern Germany and surrounding areas; formed in 1241 and most influential in the 14th century when it included over 100 towns and functioned as an independent political power; the last official assembly was held in 1669
Five Nations, Iroquois League, League of Iroquois, Six Nations
a league of Iroquois tribes including originally the Mohawk, Oneida, Onondaga, Cayuga and Seneca (the Five Nations); after 1722 they were joined by the Tuscarora (the Six Nations)
a customs union comprising Belgium and Netherlands and Luxembourg
Type of:
political entity, political unit
a unit with political responsibilities

n an organization of employees formed to bargain with the employer

“you have to join the union in order to get a job”
brotherhood, labor union, trade union, trades union
show 6 types...
hide 6 types...
industrial union, vertical union
a labor union that admits all workers in a given industry irrespective of their craft
craft union
a labor union whose membership is restricted to workers in a particular craft
company union
a union of workers for a single company; a union not affiliated with a larger union
I.W.W., IWW, Industrial Workers of the World
a former international labor union and radical labor movement in the United States; founded in Chicago in 1905 and dedicated to the overthrow of capitalism; its membership declined after World War I
Teamsters Union
an industrial union of truck drivers and chauffeurs and warehouse workers
United Mine Workers, United Mine Workers of America
an industrial union of mine workers in North America
Type of:
organisation, organization
a group of people who work together

adj of trade unions

“the union movement”
union negotiations”
“a union-shop clause in the contract”
requiring union membership
organised, organized, unionised, unionized
being a member of or formed into a labor union
not belonging to or not allowing affiliation with a trade union
not requiring union membership
nonunionised, nonunionized, unorganised, unorganized
not affiliated in a trade union
show more antonyms...

n the state of being a married couple voluntarily joined for life (or until divorce)

“God bless this union
marriage, matrimony, spousal relationship, wedlock
show 17 types...
hide 17 types...
having two spouses at the same time
common-law marriage
a marriage relationship created by agreement and cohabitation rather than by ceremony
endogamy, inmarriage, intermarriage
marriage within one's own tribe or group as required by custom or law
exogamy, intermarriage
marriage to a person belonging to a tribe or group other than your own as required by custom or law
marriage of convenience
a marriage for expediency rather than love
an unsuitable alliance (especially with regard to marriage)
the state of having only one husband at a time
monogamousness, monogamy
having only one spouse at a time
open marriage
a marriage in which each partner is free to enter into extraneous sexual relationships without guilt or jealousy from the other
the state of a husband whose wife has committed adultery
having more than one spouse at a time
a Shiite tradition of temporary marriage permitted in Iran that allows a couple to specify the terms of their relationship; can last from a few minutes to 99 years
a marriage with a person of inferior social status
having only one wife at a time
serial monogamy
a succession of short monogamous relationships (as by someone who undergoes multiple divorces)
having more than one husband at a time
having more than one wife at a time
Type of:
marital status
the condition of being married or unmarried

n the act of pairing a male and female for reproductive purposes

conjugation, coupling, mating, pairing, sexual union
show 9 types...
hide 9 types...
assortative mating
mating of individuals having more traits in common than likely in random mating
disassortative mating
mating of individuals having traits more dissimilar than likely in random mating
cross, crossbreeding, crossing, hybridisation, hybridization, hybridizing, interbreeding
(genetics) the act of mixing different species or varieties of animals or plants and thus to produce hybrids
the act of mating closely related individuals
service, servicing
the act of mating by male animals
dihybrid cross
hybridization using two traits with two alleles each
monohybrid cross
hybridization using a single trait with two alleles (as in Mendel's experiments with garden peas)
reciprocal, reciprocal cross
hybridization involving a pair of crosses that reverse the sexes associated with each genotype
test-cross, testcross
a cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait so the unknown genotype can be determined from that of the offspring
Type of:
sex, sex activity, sexual activity, sexual practice
activities associated with sexual intercourse

n healing process involving the growing together of the edges of a wound or the growing together of broken bones

Type of:
the natural process by which the body repairs itself

n a device on a national flag emblematic of the union of two or more sovereignties (typically in the upper inner corner)

Type of:
an emblematic design (especially in heraldry)

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, Vocabulary.com can put you on the path to systematic vocabulary improvement.